Eleven years ago, gene therapy — where defective genes are snipped out of DNA and replaced with healthy ones — became a household name. A landmark paper proved that scientists could precisely manipulate DNA in ways previously thought unimaginable using CRISPR-Cas9, an editing tool adapted from the immune system found in some bacteria. Almost overnight, the idea of designer babies, kill-switch mosquitoes, and cancer-off buttons stormed into mainstream imagination.
